The Human Brain :
The Triune Brain
The Triune Brain
The three parts which make up the human brain:
The neurologist Paul MacLean first proposed the hypothesis of the triune (or three-part) brain in the early 1950s. Its elegant simplicity captured the attention of both the scientific and general communities and the concept of the triune brain has become a very influential model in the ensuing years. Basically, the 3 parts that make up the triune brain are as follows:
The reptile brain or brain stem and related structures is lowest on the evolutionary totem pole. Aside from being responsible for our being able to breathe or have a heart beat without having to think about it, the reptile brain also controls our baser instincts: it is the home of what neuro-science undergrads call the “4 F’s” of brain function: “Feeding, fighting, fleeing and reproduction.”
Next on the evolutionary scale is the mammal brain or limbic system: Ever wished you were your pet dog? All you need to care about is keeping warm and fed. That done, everything’s sweet. It’s the pesky reptile brain that gets the mammal brain in trouble. Unlike the reptile brain, which will eat its young without giving it a thought, the mammal brain is capable of displaying a range of emotions and is able to function as part of a social hierarchy.
The third part of the trinity is the primate brain. The primate brain makes up most of the brain’s mass. It is responsible for our higher functions, such as speech and logical reasoning.
At first glance, this classically Darwinian model of the brain seems to close the door on any exploration of the brain beyond its obvious function as a rather marvelous evolutionary mechanism. Even the father of modern dualistic thought, Rene Descartes, found a place for the soul in the brain – the pineal gland. But in Maclean’s model there is none.
Or is there? At about the same time that MacLean’s triune brain model trickled down through academic circles, an unknown Soul Surfer with no academic or theological credits to his name asked himself some questions – questions that puzzle researchers to this day – and delved deeper into the triune brain. A WWII veteran, folk singer and television host who went by the name of TDA Lingo wanted to know why, if the largest part of the brain was the sophisticated primate brain, did we so often behave like deranged reptiles? And why, if we were basically primates, did our higher selves occasionally soar with creative thoughts, feel love, compassion, empathy and a deep appreciation for “the true, the good and the beautiful”? Lingo found his answers in the amygdala and the frontal lobes.
Basically, the amygdala is responsible for our brain’s “fight or flight” mechanism. When operating properly, it performs the very helpful task of warning us of danger. In Lingo’s day, most researchers agreed that this was all it did. Lingo disagreed and subsequent research has confirmed his hypothesis that the amygdala has a potentially positive function that is largely unknown because it is so rarely utilized.
The frontal lobes are, as the name implies, located in the front of the brain, just behind the forehead. Until recently they were considered of little importance – hence frontal lobotomies were almost routinely performed on mentally disturbed patients. But recent studies have shown them to have far greater potential importance than previously assumed: if we are indeed evolutionary animals (and evidence is mounting that we are not – or not only that), then the frontal lobes are quite possibly the home of our highest human potential. Brain scans performed on meditating Buddhist monks, accomplished yogis and Catholic nuns engaged in contemplative prayer have shown that the frontal lobes become highly activated when one is in a state of religious ecstasy. TDA Lingo came to this same conclusion back in the 1950s, but it has taken this long for the scientific community to catch up with him.
It was a simple technique for stimulating “frontal lobes bliss” through conscious amygdala stimulation that awakened this soul surfer’s interest in the brain. After having practiced yoga and meditation, attended seminars and workshops and read countless books on mysticism over the course of a lifetime, the technique seemed too absurdly easy to be effective – but it worked. Determined to find the loophole in the theory, I began to study the brain and discovered that not only did the technique work, the science behind it was sound. I urge the reader to read my article, The Crazy Wisdom of TDA Lingo and try “amygdala clicking” yourself.
Let’s take a look at the triune brain from another perspective. In the diagram above, we have our three-tiered triune brain with what appears to be an emerging fourth tier in the frontal lobes. Each tier can be said to represent a stage of consciousness evolution. The state of consciousness we’re operating from – collectively or individually – depends on which part of the brain is predominantly running the show.
It is important to note that the higher stages of consciousness both include and transcend the lower stages. The reptile brain, for instance, is incapable of working co-operatively with others, even if it would be to its advantage to do so. Its only goal is to stay alive. The frontal lobes, on the other hand, see the bigger picture. While survival remains an issue, an individual operating predominantly from the dictates of the frontal lobes has the capacity to behave charitably or unselfishly if such behaviour serves the greater good. Outside the three ‘bubbles’ of individual consciousness, I’ve included a fourth – the transcendent. This is, in this soul surfer’s opinion, where the purely Darwinian limits of the triune brain become apparent and we have to start looking elsewhere for our answers.
When we split the brain down the middle to look at its structure, we were only doing what nature has already done. Our brains are divided into two hemispheres and these two halves behave so very differently that they often seem like separate brains – a left brain and a right brain. It’s time to move on to the Split Brain.